Electron tube mount



June 24, 1958 H. RUZINSKY 2,840,735

ELECTRON TUBE MOUNT I Filed Jan. 4, 1956 ii, 1/ 2!? r 14' I I -/4 6 40 i I-40 IN V EN TOR.

United States Patent ELECTRON TUBE MOUNT Herbert Ruzinsky, New York, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application January 4, 1956, Serial No. 557,310

11 Claims. (Cl. 313-1) This invention is concerned with the art of electron tube mounts, and relates in particular to improvements in electron tube mounts having a plurality of elongated electrode cages of different axial extents. An electrode cage of an electron tube commonly includes electrodes that comprise at least a cathode and an anode, and a pair of insulating spacer plates sandwiching these elec-v trodes between them for suitably positioning the electrodes relative to each other.

Previous plural cage electron tube mounts have usually had all of the electrodes of the separate cages assembled between a single pair of spacer plates. The practice of mounting the electrodes of all of the cages between a single pair of spacer plates has usually required the use of cages having the same axial extents. However, it is often desirable to mount within a single electron tube envelope a plurality of electrode cages having different axial extents and with each cage substantially completely shielded from the other cage or cages. For example, it is sometimes desirable, in the interest of space or cost economy, to include in the same envelope an audio frequency power output type cage and a radio frequency amplifier type cage. The power output cage usually requires a relatively large anode area inorder to dissipate the heat generated during normal operation of the cage; such a cage, therefore, usually has relatively large axial and transverse extents. On the other hand, the radio frequency amplifier cage is usually of a relatively small size, and has relatively small axial'and transverse extents, for better performance at the radio frequencies. In addition to the problem of mounting cages of different axial extents within the same tube, a further problem is often encountered. This problem concerns shielding. 'Sincethe radio frequency amplifier cage is usually required to handle relatively low level signals, this cage is greatly susceptible to electrostatic forces adjacent to the cage. However, the nature of a power output cage is such that it handles electrostatic forces of a relatively high magnitude.

It is therefore an object of the invention to provide an improved plural cage electron tube, mount having a plurality of elongated, self-supporting electrode cages of different axial extents.

It is another object of the invention to provide an improved plural cage electron tube mount which is comprised of a plurality of elongated electrode cages of different axial extents and wherein the cages are substantially completely shielded one from the other.

It is yet another object of the invention to provide an improved elongated electron tube mount incorporating a relatively large power output type cage and a relatively small radio frequency amplifier type cage, and wherein the cages have different axial extents, and wherein the radio frequency amplifier cage is substantially completely shielded from the other cage.

The foregoing and related objects are accomplished in an electron tube mount comprising two elongated electrode cages having different axial extents. Thetwo cages have a common spacer plate engaging adjacent ends of the cages and each cage has a second spacer plate. The shorter cage is axially spaced from the second plate of the larger cage and has an element fixed to and extending beyond the free end of the shorter cage and fixed to the second plate of the larger cage.

The invention is described in greater detail in the drawing where like numerals refer to like parts, andwhereinz' Fig. l is a partially cut-away side elevational view of an electron tube mount of the invention;

Fig. 2 is a sectional view taken through line 2-2 of Fig. 1;

Fig. 3 is a sectional view taken through line 3-3 of Fig. 2; and

Fig. 4 is an enlarged perspective view of a shielding element used in the tube of Fig. 1.

Fig. 1 illustrates an electron tube 2 having electrode access terminals or prongs 4 at one end thereof and an envelope 6 containing a plural cage mount 10 comprised of two self-supporting, side-by-side, elongated cages 12 and 14 having different axial extents.

The longer cage 12, in one example, may be a power output cage of a type often used in single cage mounts of tubes of the octal base variety. This type of cage is characterized in having relatively large axial and transverse extents in order to better aid in dissipating the relatively large amount of heat generated by the cage during normal operation. The other cage 14, in this example, is of a type ordinarily used in tubes of the miniature variety and may be a radio frequency amplifier cage useful in the first stage of amplification in the tuning section of a television receiver.

The cages 12 and 14 have, at one end thereof, a common, flat spacer plate 16. The first cage 12 has, at the other end thereof, a second spacer plate 18. The second cage 14 is axially spaced from the second plate 18 and has an element 20 fixed to and extending beyond its other, free end and fixed to the second plate 18. The element 20 thus serves to bridge the gap between the free end of the shorter cage 14 and the second spacer'p'late 18.

As illustrated in Figs. 1, 2, and 3, the longer cage 12 has, mounted between the first and second spacer plates 16 and 18, a cathode 22 surrounded by three wound grids 24, 26, and 28. The grids, in turn, are surrounded by a sheet metal anode 30. The shorter cage 14 is comprised, at one end thereof, of a first spacer plate 31 in contact with the common spacer plate 16 and has, at the other end thereof, a second spacer plate 32. These spacer plates 16, 31, and 32 sandwich between them the electrodes of cage 14; the electrodes comprise a cathode 34 surrounded by a wound grid 36 which is, in turn, surrounded by a tubular, sheet metal anode 38.

Each of the electrodes referred to has an electrode extension portion 22', 24', 26', 28', 30', 34, 36', and 38 at each of its opposite ends, each electrode extending through the common spacer plate. 16 and the other spacer plates of its cage. The electrodesare maintained in position within their cages by, means of the plates 16, 18, 31, and 32.

The element 20 (Fig. 4) referred to is preferably comprised of a metallic material having a relatively high magnetic permeability. The reason for this is that such a material will not only serve to electrostatically shield the two cages 12 and 14 from each other, but will also magnetically shield each of them from the other. The element 20 has three fiat sides 40, 42, and 44. Each of the sides has, at opposite ends thereof, extension portions or cars 40, 42', and 44'. One of the sides 44 of the element 20 extends for an axial distance sufficient to bridge the distance between the common spacer plate 16 and the second spacer plate 18 of the longer cage 12.

The other two sides 40 and 42 of the element have axial Patented June .24, 1958 extents suflicient to bridge the distance between the common spacer plate 16 and the second spacer plate 32 of the shorter cage. The longer side 44 of the element 20 is disposed between the two cages 12 and 14 while the shorter sides 40 and 42 are positioned on opposite sides of the shorter cage 14., The element 20 thus serves to shield the two cages each from the other.

Each of the spacer plates 16, 18, 31, and 32 has apertures adapted to receive the electrode'extending portions 22 through 38 of the electrodes referred to as well as the cars 40, 42', and 44"0f the element 20. The electrodes and the element are thus each secured between at least a pair of spacer plates for positioning and integrating the spacer plates, the electrodes, and the element 20, into a composite, two-cage electron tube mount.

Thus it is seen that the invention provides an improved plural cage electron tube mount having a pair of elongated electrode cages of different axial extents, and wherein the cages are magnetically as well as electrostatically shielded one from the other.

What is claimed is:

1. An electron tube mount comprising a plurality of elongated electrode cages in side-by-side relation and having different axial extentsand means including an element shielding each of said cages from the other fixing said cages in spaced apart relation.

2. An electron tube mount comprising two elongated electrode cages having difierent axial extents and having a common spacer plate, the cage having the greater axial extent having a second spacer plate spaced apart from said common plate, and the cage having a less axial extent being axially spaced from said second plate and having an element fixed to and extending axially beyond its 'free end and fixed to said second spacer plate.

3. An electron tube mount comprising two elongated electrode cages having difierent axial extents and having only one common spacer plate, one cage having a greater axial extent and having a second spacer plate and the other cage having a less axially extent and being axially spaced from said secondplate and having a shield shielding said cages from each other and fixed to and extending axially beyond the free end of said other cage and fixed to said second spacer plate.

4. A multi-cage assembly for an electron tube, comprising two electrode assemblies each having two spacer pla'tes, one spacer plate of one assembly being in overlapping contact relation with one spacer plate of the other assembly, the other spacer plate of said one assemblybe'ing in overlapping and spaced relation with the other spacer plate of said other assembly, and means locking adjacent spacer plates together.

'5. A multi-cage assembly for an electron tube, comprising two electrode assemblies each having two spacer plates, one spacerplate of one assembly being in overlapping contact relation with one spacer plate ofthe other assembly, the other spacer plate of said one assembly being in overlapping and spaced relation with the other spacer plate of said other assembly, and a support 6. An electron tube mount comprising two elongated electrode cages having different axial extents andihaving only one common spacerplate, the longer of said cages having a second spacer plate and the shorter of said cages being axially spaced 'from said second .p'late,.said' shorter cagehaving a shield element shielding said cages from each other and fixed to and extending axially beyond said shorter cage and fixed to said second spacer plate, said shorter cage having a pair of spacer plates fixed betweensaid common plate and said second plate, whereby each of said two elongated electrode cages is adapted to be separately assembled between and fixed to a pair of spacer plates. a

17. An electron tube mount comprising two elongated, plural electrode cages having different axial extents and having only one common spacer plate, the cage having a greater axial extent having a second spacer plate and the shorter of said cages being axially spaced from said second plate, the shorter cage having a shield of magnetically permeable material positioned between the electrodes of one cage and the electrodes of the other cage to electrostatically and magnetically shield said cages each from the other, said shield being fixed to and extending axially beyond the shorter cage and fixed to said second spacer plate.

8. An electron tube mount comprising two elongated electrode cages having different axial extents and having only .one common spacer plate, the longer cage having a second spacer plateand the shorter cage being axially spaced from said second plate and having an element fixed to and extending axially beyond the shorter cage and fixed to said second spacer plate, said shorter cage having a pair of spacer plates fixed between said common plate and said second plate and with one plate of said pair lapped against said common plate and the other plate of said pair axially spaced between both said common plate and said second plate, whereby each of a pair of elongated electrode cages having diiferent axial extents is adapted to be separately assembled between and fixed to a pair of spacer plates and the pair of cages fixed into a unitary structure.

9. An electron tube mount comprising two elongated electrode cages having different axial extents and having a common spacer plate, the longer cage having a second spacer plate and the shorter cage being axially spaced from said second plate, and a shielding element spanning the distance between said common plate and said second plate and being fixed to the shorter cage for securing said shorter cage to said longer cage while shielding said cages each from the other.

10. An electron tube mount comprising two elongated electrode cages having different axial extents and having a common spacer plate, the longer cage having a second spacer plate and the shorter cage being axially spaced from said second plate, and a shielding element spanning the distance'between said common plate and said second plate and being fixed to said shorter cage securing said shielding element and said shorter cage to said second plate while shielding the cages each from the other, said shorter cage having a pair of spacer plates fixed between said common plate and said second plate, said element engaging each of the plates of said pair, whereby each of a pair of elongated electrode cages of diiferent axial extents is adapted to be separately assembled between and fixed to a pair of spacer plates and thepair of cages fixed into a unitary structure. p

'11. An electron tube .mount comprising two elongated electrode cages having different axial extents and having a commonspacer plate, thelonger cage having a second spacer plate and the shorter cage being axially spaced from said second p'late,.and a shielding element spanning the distance between saidcommon plate and said second .,plate and being fixed to the shorter cage securing said element fixing said onesof said spacer plates .to each shielding element and said shorter cage to said second plate while shielding the cages each from the other, said shorter cage having a pair of spacer plates fixed between said common plate and said second plate, said element engaging each of the plates of said pair, one of the plates 1 of said ,pair being lapped against said common plate and secured thereto by said element and the other plate of said pair being axially spaced from said common plate and said second plate.

References Cited in the file of this patent 

